To form a gasket in a shape suitable for simplifying attaching work of the gasket to a door corner with a small curvature radius.

A support body, especially for a sealing gasket for being attached to both automobile doors, has at least one corner with the small curvature radius. The gasket comprises at least a flexible or semi-rigid portion 3 for fixing to be fixed to the support body by adhesive tape 7 and an elastically deformable tubular portion 5 for providing the sealing. When the gasket is attached to the support body, the tubular portion 5 undergoes deformation occupying a certain region substantially positioned in a region occupied by the cross sectional surface of the gasket when the cross sectional surface of the tubular portion 5 lies in a release state in the corner of the support body.